In thermally assisted optical/magnetic data storage, information bits are recorded on a layer of a storage medium at elevated temperatures, and the heated area in the storage medium determines the data bit dimension. Heat assisted magnetic recording (HAMR) generally refers to the concept of locally heating a recording medium to reduce the coercivity of the recording medium so that the applied magnetic writing field can more easily direct the magnetization of the recording medium during the temporary magnetic softening of the recording medium caused by the heat source. For HAMR, a tightly confined, high power laser light spot is used to preheat a portion of the recording medium to substantially reduce the coercivity of the heated portion. Then the heated portion is subjected to a magnetic field that sets the direction of magnetization of the heated portion. In this manner the coercivity of the medium at ambient temperature can be much higher than the coercivity during recording, thereby enabling stability of the recorded bits at much higher storage densities and with much smaller bit cells. Heat assisted magnetic recording can be applied to any type of magnetic storage media, including tilted media, longitudinal media, perpendicular media and patterned media.
One of the requirements for a heat assisted magnetic recording drive is an effective way to couple light from a laser diode or fiber to a coupling grating on a transducer on the slider. A number of light delivery methods have been suggested to date which require substantial changes in slider, suspension, or actuator arm (E-block) designs. In most cases, the suggested structures alter the inertia, moment, and/or thermal load of the head gimbal assembly or arm assembly such that the mechanical performance, robustness, and reliability of the drive system are compromised.
An alternative light delivery method which imposes minimal changes to existing HGA/actuator arm assembly would be desirable.